The functional analysis of human fertility decisions

Abstract

In the theoretical structure of new home economics models, human fertility decisions are taken so as to maximize satisfaction provided to the parents by the presence and well-being of their children and by other competing commodities. Nevertheless, the concept of utility of children fails to specify why parents benefit from the presence and well-being of their progeny. In this study, fertility choices are analyzed from an evolutionary perspective. Parents are thus expected to adopt a lifetime fertility schedule `that maximizes fitness, defined here as the product of quantity with quality of offspring. Quality refers to the probability that reproduction occurs in the next generation, a variable that is thought to depend on the amount of resources allocated by the parents to the progeny. Using multiperiod dynamic models of fertility, it is shown that an increase in wealth and income reduces time to first conceptions and increases total conceptions. However, the relationship between offspring number and income is not always positive as changes in child quality also occur. Uncertainty about future economic status favors more conservative fertility schedules. Qualitative predictions of the models are generally supported by available evidence, although much work remains to be done to estimate the models quantitatively.